Evaluation and prevalence of major central nervous system malformations: a retrospective study

OBJECTIVE Central nervous system (CNS) anomalies are the most common abnormalities of all malformations and can be diagnosed on routine prenatal ultrasonography (US). We aimed to find out fetal CNS anomaly rate in our clinic which is the referral center in the region. METHODS This is a retrospective study of 15000 pregnant women who were scanned for routine obstetric follow-up from January 2012 to July 2013 in our referral center. We diagnosed CNS anomalies in 41 fetuses by using high resolution ultrasound unit with 3.5 MHz transabdominal and 6 MHz transvaginal transducers. RESULTS CNS anomalies included 12 Chiari malformations, 2 Dandy-Walker malformations (DWM), 1 variant of Dandy-Walker syndrome (DWS), 3 iniencephalies, 15 anencephalies, 1 alobar holoprosencephaly, 2 isolated hydrocephalies, 3 hydrocephalies with cerebellar hypoplasia, 1 occipital encephalocele, 1 lumbosacral myelomeningocele accompanied with microcephaly. There were some associated anomalies in the groups that included club-foot deformities in 6 cases, ventricular septal defect (VSD) in 2 cases, polycystic kidney in 2 cases, scoliosis in 1 case, hypoplasic left ventricle in 1 case; alone atrium, single umbilical artery, echogenic focus, hydronephrosis and cleft lip and palate in the same case, and omphalocele in one. CONCLUSION Prognosis and early detection of CNS abnormalities have become an important issue because the most serious complications of major CNS anomalies are disability and getting bedridden and this situation is inevitably related to health economy. On the other hand prognosis of the fetus and family counseling is another important issue. Parents should decide whether to continue their pregnancies or not.